package com.holyliao.visitor;

import net.sf.jsqlparser.statement.select.FromItem;
import net.sf.jsqlparser.statement.select.Join;
import net.sf.jsqlparser.statement.select.OrderByElement;
import net.sf.jsqlparser.statement.select.PlainSelect;
import net.sf.jsqlparser.statement.select.SelectBody;
import net.sf.jsqlparser.statement.select.SelectItem;
import net.sf.jsqlparser.statement.select.SelectVisitor;
import net.sf.jsqlparser.statement.select.SetOperationList;
import net.sf.jsqlparser.statement.select.WithItem;

import com.holyliao.DPHelper;

public class SelectVisitorImpl implements SelectVisitor {

    // 主要工作就是实现各种底层visitor，然后在解析的时候添加条件
    // 正常的select，也就是包含全部属性的select
    @Override
    public void visit(PlainSelect plainSelect) {

        // 访问 select
        if (plainSelect.getSelectItems() != null) {
            for (SelectItem item : plainSelect.getSelectItems()) {
                item.accept(new SelectItemVisitorImpl());
            }
        }

        // 访问from
        FromItem fromItem = plainSelect.getFromItem();
        FromItemVisitorImpl fromItemVisitorImpl = new FromItemVisitorImpl();
        fromItem.accept(fromItemVisitorImpl);

        if (fromItemVisitorImpl.getSubSelect() != null) {
            plainSelect.setFromItem(fromItemVisitorImpl.getSubSelect());
            if (!DPHelper.getChangeTable()) {
                DPHelper.setChangeTable(true);
            }
        }

        // 访问where
        if (plainSelect.getWhere() != null) {
            plainSelect.getWhere().accept(new ExpressionVisitorImpl());
        }

        // 访问join
        if (plainSelect.getJoins() != null) {
            for (Join join : plainSelect.getJoins()) {
                FromItemVisitorImpl fromItemVisitorImplTemp = new FromItemVisitorImpl();
                join.getRightItem().accept(fromItemVisitorImplTemp);
                if (fromItemVisitorImplTemp.getSubSelect() != null) {
                    join.setRightItem(fromItemVisitorImplTemp.getSubSelect());
                    if (!DPHelper.getChangeTable()) {
                        DPHelper.setChangeTable(true);
                    }
                }
            }
        }

        // 访问 order by
        if (plainSelect.getOrderByElements() != null) {
            for (OrderByElement orderByElement : plainSelect
                    .getOrderByElements()) {
                orderByElement.getExpression().accept(
                        new ExpressionVisitorImpl());
            }
        }

        // 访问group by having
        if (plainSelect.getHaving() != null) {
            plainSelect.getHaving().accept(new ExpressionVisitorImpl());
        }

    }

    // set操作列表
    @Override
    public void visit(SetOperationList setOpList) {
        for (SelectBody plainSelect : setOpList.getSelects()) {
            plainSelect.accept(new SelectVisitorImpl());
        }
    }

    // with项
    @Override
    public void visit(WithItem withItem) {
        withItem.getSelectBody().accept(new SelectVisitorImpl());
    }

}